Left bundle branch pacing versus left ventricular septal pacing as a primary procedural endpoint during left bundle branch area pacing: Evaluation of two different implant strategies.

INTRODUCTION: Implant procedure features and clinical implications of left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) have not been yet fully described. We sought to compare two different left bundle branch area pacing (LBBAP) implant strategies: the first one accepting LVSP as a procedural endpoint and the second one aiming at achieving LBBP in every patient in spite of evidence of previous LVSP criteria. METHODS: LVSP was accepted as a procedural endpoint in 162 consecutive patients (LVSP strategy group). In a second phase, LBBP was attempted in every patient in spite of achieving previous LVSP criteria (n = 161, LBBP strategy group). Baseline patient characteristics, implant procedure, and follow-up data were compared. RESULTS: The final capture pattern was LBBP in 71.4% and LVSP in 24.2% in the LBBP strategy group compared to 42.7% and 50%, respectively, in the LVSP strategy group. One hundred and eighty-four patients (57%) had proven LBB capture criteria with a significantly shorter paced QRS duration than the 120 patients (37%) with LVSP criteria (115 ± 9 vs. 121 ± 13 ms, p < .001). Implant parameters were comparable between the two strategies but the LBBP strategy resulted in a higher rate of acute septal perforation (11.8% vs. 4.9%, p = .026) without any clinical sequelae. Patients with CRT indications significantly improved left ventricular ejection fraction (LVEF) during follow-up irrespective of the capture pattern (from 35 ± 11% to 45 ± 14% in proven LBBP, p = .024; and from 39 ± 13% to 47 ± 12% for LVSP, p = .003). The presence of structural heart disease and baseline LBBB independently predicted unsuccessful LBB capture. CONCLUSION: The LBBP strategy was associated with comparable implant parameters than the LVSP strategy but resulted in higher rates of septal perforation. Proven LBB capture and LVSP showed comparable effects on LVEF during follow-up.

Conduction System Pacing for Cardiac Resynchronization Therapy.

Cardiac resynchronization therapy (CRT) via biventricular pacing (BiVP-CRT) is considered a mainstay treatment for symptomatic heart failure patients with reduced ejection fraction and wide QRS. However, up to one-third of patients receiving BiVP-CRT are considered non-responders to the therapy. Multiple strategies have been proposed to maximize the percentage of CRT responders including two new physiological pacing modalities that have emerged in recent years: His bundle pacing (HBP) and left bundle branch area pacing (LBBAP). Both pacing techniques aim at restoring the normal electrical activation of the ventricles through the native conduction system in opposition to the cell-to-cell activation of conventional right ventricular myocardial pacing. Conduction system pacing (CSP), including both HBP and LBBAP, appears to be a promising pacing modality for delivering CRT and has proven to be safe and feasible in this particular setting. This article will review the current state of the art of CSP-based CRT, its limitations, and future directions.

Acute performance of stylet driven leads for left bundle branch area pacing: A comparison with lumenless leads.

Background: Lumenless leads (LLLs) are widely used for left bundle branch area pacing (LBBAP). Recently, stylet-driven leads (SDLs) have also been used for LBBAP. Objective: The purpose of this study was to evaluate the acute performance of SDLs during LBBAP in comparison with LLLs. Methods: Consecutive patients undergoing LBBAP for bradycardia or cardiac resynchronization therapy indications at 2 high-volume, early conduction system pacing adopters, tertiary centers were included from January 2019 to July 2023. Patients received either SDLs or LLLs at the discretion of the implanting physician. Acute performance and follow-up data of both lead types were evaluated. Results: A total of 925 LBBAP implants were included, 655 using LLLs and 270 using SDLs. Overall, LBBAP acute success was significantly higher with LLLs than SDLs (95.3% vs 85.1%, respectively; P <.001) even after the learning curve (97% vs 86%; P = .013). LLLs were implanted in more mid-basal septal positions in comparison with SDLs, which tended to be implanted in more inferior and mid-apical septal positions. Acute lead-related complications were higher with SDLs than LLLs (15.9% vs 6.1%, respectively; P <.001) with 15 cases of lead damage during implant (4.4% vs 0.5%; P <.001) but decreased with acquired experience and were comparable in the last 100 patients included in each group. Lead implant and fluoroscopy times were shorter for SDLs, with lead dislodgment occurring in 0.9% with LLLs and 1.5% with SDLs (P = .489). Conclusion: Acute lead performance proved to be different between LLLs and SDLs. A specific learning curve should be considered for SDLs even for implanters with extensive previous experience with LLLs.

Safety and feasibility of conduction system pacing in patients with congenital heart disease.

INTRODUCTION: Conduction system pacing (CSP) has emerged as an ideal physiologic pacing strategy for patients with permanent pacing indications. We sought to evaluate the safety and feasibility of CSP in a consecutive series of unselected patients with congenital heart disease (CHD). METHODS: Consecutive patients with CHD in which CSP was attempted were included. Safety and feasibility, implant tools and electrical parameters at implant and at follow-up were evaluated. RESULTS: A total of 20 patients were included (10 with a previous device). A total of 10 patients had complex forms of CHD, 9 moderate defects and 1 a simple defect. CSP was achieved in 75% of cases (10 His bundle pacing, 5 left bundle branch pacing) with left ventricular septal pacing in the remaining 5 patients. Procedure times and fluoroscopy times were prolongued (126 ± 82 min and 27 ± 30 min, respectively). Ventricular lead implant times widely varied ranging from 4 to 115 min, (mean 31 ± 28 min) and the use of multiple delivery sheaths was frequent (50%). The QRS width was reduced from 145 ± 36 ms at baseline to 116 ± 18 ms with CSP. Implant electrical parameters included: CSP pacing threshold 0.95 ± 0.65 V; R wave amplitude 9.2 ± 8.8 mV and pacing impedance 632 ± 183 Ohms, and remained stable at a median follow-up of 478 days (interquartile range: 225-567). Systemic ventricle systolic function and NYHA class (1.50 ± 0.51 vs. 1.10 ± 0.31; p = .008) significantly improved at follow-up. Lead revision was required in one patient at Day 4. CONCLUSIONS: Permanent CSP is safe and feasible in patients with CHD although implant technique is complex.

Influence of baseline inducibility and activation mapping on ablation outcomes in patients with structural heart disease and ventricular tachycardia.

INTRODUCTION: Stand-alone substrate ablation has become a standard ventricular tachycardia (VT) ablation strategy. We sought to evaluate the influence of baseline VT inducibility and activation mapping on ablation outcomes in patients with structural heart disease (SHD) undergoing VT ablation. METHODS: Single center, observational and retrospective study including consecutive patients with SHD and documented VT undergoing ablation. Baseline VT induction was attempted before ablation in all patients and VT activation mapping performed when possible. Ablation was guided by activation mapping for mappable VTs plus substrate ablation for all patients. Ablation outcomes and complications were evaluated. RESULTS: One hundred and sixty patients were included and were classified in three groups according to baseline VT inducibility:group 1 (non inducible, n = 18), group 2 (1 VT morphology induced, n = 53), and group 3 (>1 VT morphology induced, n = 89). VT activation mapping was possible in 35%. After a median follow-up of 38.5 months, baseline inducibility of greater than 1 VT morphology was associated with a significant incidence of VT recurrence (42% for group 3 vs. 15.1% for group 2% and 5.6% for group 1, Log-rank p < .0001) and activation mapping with a lower rate of VT recurrence (24% vs. 36.3%, Log-rank p = .035). Baseline inducibility of greater than 1 VT morphology (hazards ratio [HR]: 12.05, 95% confidence interval [CI]: 1.60-90.79, p = .016) was an independent predictor of VT recurrence while left ventricular ejection fraction less than 30% (HR: 1.93, 95% CI: 1.13-3.25, p = .014) and advanced heart failure (HR: 4.69, 95% CI: 2.75-8.01, p < .0001) were predictors of mortality or heart transplantation. Complications occurred in 11.2% (5.6% hemodynamic decompensation). CONCLUSION: Baseline VT inducibility and activation mapping may add significant prognostic information during VT ablation procedures.

Natural History and Risk Stratification in Andersen-Tawil Syndrome Type 1.

BACKGROUND: Andersen-Tawil Syndrome type 1 (ATS1) is a rare arrhythmogenic disorder, caused by loss-of-function mutations in the KCNJ2 gene. We present here the largest cohort of patients with ATS1 with outcome data reported. OBJECTIVES: This study sought to define the risk of life-threatening arrhythmic events (LAE), identify predictors of such events, and define the efficacy of antiarrhythmic therapy in patients with ATS1. METHODS: Clinical and genetic data from consecutive patients with ATS1 from 23 centers were entered in a database implemented at ICS Maugeri in Pavia, Italy, and pooled for analysis. RESULTS: We enrolled 118 patients with ATS1 from 57 families (age 23 ± 17 years at enrollment). Over a median follow-up of 6.2 years (interquartile range: 2.7 to 16.5 years), 17 patients experienced a first LAE, with a cumulative probability of 7.9% at 5 years. An increased risk of LAE was associated with a history of syncope (hazard ratio [HR]: 4.54; p = 0.02), with the documentation of sustained ventricular tachycardia (HR 9.34; p = 0.001) and with the administration of amiodarone (HR: 268; p < 0.001). The rate of LAE without therapy (1.24 per 100 person-years [py]) was not reduced by beta-blockers alone (1.37 per 100 py; p = 1.00), or in combination with Class Ic antiarrhythmic drugs (1.46 per 100 py, p = 1.00). CONCLUSIONS: Our data demonstrate that the clinical course of patients with ATS1 is characterized by a high rate of LAE. A history of unexplained syncope or of documented sustained ventricular tachycardia is associated with a higher risk of LAE. Amiodarone is proarrhythmic and should be avoided in patients with ATS1.

Changes in the spatial distribution of the Purkinje network after acute myocardial infarction in the pig.

Purkinje cells (PCs) are more resistant to ischemia than myocardial cells, and are suspected to participate in ventricular arrhythmias following myocardial infarction (MI). Histological studies afford little evidence on the behavior and adaptation of PCs in the different stages of MI, especially in the chronic stage, and no quantitative data have been reported to date beyond subjective qualitative depictions. The present study uses a porcine model to present the first quantitative analysis of the distal cardiac conduction system and the first reported change in the spatial distribution of PCs in three representative stages of MI: an acute model both with and without reperfusion; a subacute model one week after reperfusion; and a chronic model one month after reperfusion. Purkinje cells are able to survive after 90 minutes of ischemia and subsequent reperfusion to a greater extent than cardiomyocytes. A decrease is observed in the number of PCs, which suffer reversible subcellular alterations such as cytoplasm vacuolization, together with redistribution from the mesocardium-the main localization of PCs in the heart of ungulate species-towards the endocardium and perivascular epicardial areas. However, these changes mainly occur during the first week after ischemia and reperfusion, and are maintained in the chronic stages. This anatomical substrate can explain the effectiveness of endo-epicardial catheter ablation of monomorphic ventricular tachycardias in the chronic scar after infarction, and sets a basis for further electrophysiological and molecular studies, and future therapeutic strategies.

Temporal Trends and Temperature-Related Incidence of Electrical Storm: The TEMPEST Study (Temperature-Related Incidence of Electrical Storm).

BACKGROUND: The occurrence of ventricular tachyarrhythmias seems to follow circadian, daily, and seasonal distributions. Our aim is to identify potential temporal patterns of electrical storm (ES), in which a cluster of ventricular tachycardias or ventricular fibrillation, negatively affects short- and long-term survival. METHODS AND RESULTS: The TEMPEST study (Circannual Pattern and Temperature-Related Incidence of Electrical Storm) is a patient-level, pooled analysis of previously published data sets. Study selection criteria included diagnosis of ES, absence of acute coronary syndrome as the arrhythmic trigger, and ≥10 patients included. At the end of the selection and collection processes, 5 centers had the data set from their article pooled into the present registry. Temperature data and sunrise and sunset hours were retrieved from Weather Underground, the largest weather database available online. Total sample included 246 patients presenting with ES (221 men; age: 65±9 years). Each ES episode included a median of 7 ventricular tachycardia/ventricular fibrillation episodes. Fifty-nine percent of patients experienced ES during daytime hours (P<0.001). The prevalence of ES was significantly higher during workdays, with Saturdays and Sundays registering the lowest rates of ES (10.4% and 7.2%, respectively, versus 16.5% daily mean from Monday to Friday; P<0.001). ES occurrence was significantly associated with increased monthly temperature range when compared with the month before (P=0.003). CONCLUSIONS: ES incidence is not homogenous over time but seems to have a clustered pattern, with a higher incidence during daytime hours and working days. ES is associated with an increase in monthly temperature variation. CLINICAL TRIAL REGISTRATION: https://www.crd.york.ac.uk. Unique identifier: CRD42013003744.

Endo-epicardial versus only-endocardial ablation as a first line strategy for the treatment of ventricular tachycardia in patients with ischemic heart disease.

BACKGROUND: Epicardial ablation has shown improvement in clinical outcomes of patients with ischemic heart disease (IHD) after ventricular tachycardia (VT) ablation. However, usually epicardial access is only performed when endocardial ablation has failed. Our aim was to compare the efficacy of endocardial+epicardial ablation versus only endocardial ablation in the first procedure in patients with IHD. METHODS AND RESULTS: Fifty-three patients with IHD, referred for a first VT ablation to our institution, from 2012 to 2014, were included. They were divided in 2 groups according to enrollment time: from May 2013, we started to systematically perform endo-epicardial access (Epi-Group) as first-line approach in consecutive patients with IHD (n=15). Patients who underwent only an endocardial VT ablation in their first procedure (Endo-Group) included patients with previous cardiac surgery and the historical (before May 2013; n=35). All late-potentials in the scar zone were eliminated, and if VT was tolerated, critical isthmuses were also approached. The end point was the noninducibility of any VT. During a median follow-up of 15±10 months, the combined end point (hospital or emergency admission because of a ventricular tachycardia or reablation) occurred in 14 patients of the Endo-group and in one patient in the Epi-group (event-free survival curves by Grey-test, P=0.03). Ventricular arrhythmia recurrences occurred in 16 and in 3 patients in the Endo and Epi-Group, respectively (Grey-test, P=0.2). CONCLUSIONS: A combined endocardial-epicardial ablation approach for initial VT ablation was associated with fewer readmissions for VT and repeat ablations. Further studies are warranted.

Scar Extension Measured by Magnetic Resonance-Based Signal Intensity Mapping Predicts Ventricular Tachycardia Recurrence After Substrate Ablation in Patients With Previous Myocardial Infarction.

OBJECTIVES: The aim of this study was to determine if noninvasive measurement of scar by contrast-enhanced magnetic resonance imaging (MRI)-based signal intensity (SI) mapping predicts ventricular tachycardia (VT) recurrence after endocardial ablation. BACKGROUND: Scar extension on voltage mapping predicts VT recurrence after ablation procedures. METHODS: A total of 46 consecutive patients with previous myocardial infarction (87% men, mean age 68 ± 9 years, mean left ventricular ejection fraction 36 ± 10%) who underwent VT substrate ablation before the implantation of a cardioverter-defibrillator were included. Before ablation, contrast-enhanced MRI was performed, and areas of endocardial and epicardial scarring and heterogeneous tissue were measured; averaged subendocardial and subepicardial signal intensities were projected onto 3-dimensional endocardial and epicardial shells in which dense scar, heterogeneous tissue, and normal tissue were differentiated. RESULTS: During a mean follow-up period of 32 ± 24 months 17 patients (37%) had VT recurrence. Patients with recurrence had larger scar and heterogeneous tissue areas on SI maps in both endocardium (81 ± 27 cm2 vs. 48 ± 21 cm2 [p = 0.001] and 53 ± 21 cm2 vs. 30 ± 15 cm2 [p = 0.001], respectively) and epicardium (76 ± 28 cm2 vs. 51 ± 29 cm2 [p = 0.032] and 59 ± 25 cm2 vs. 37 ± 19 cm2 [p = 0.008]). In the multivariate analysis, MRI endocardial scar extension was the only independent predictor of VT recurrence (hazard ratio: 1.310 [per 10 cm2]; 95% confidence interval: 1.051 to 1.632; p = 0.034). Freedom from VT recurrence was higher in patients with small endocardial scars by MRI (<65 cm2) than in those with larger scars (≥65 cm2) (85% vs. 20%, log-rank p = 0.018). CONCLUSIONS: Pre-procedure endocardial scar extension assessment by contrast-enhanced MRI predicts VT recurrence after endocardial substrate ablation. This information may be useful to select patients for ablation procedures.

[Outcome of patients with local complications at the site of an implantable device]. / Evolución de los pacientes con complicaciones locales en la bolsa del generador de un dispositivo implantable.

OBJECTIVE: The recommendations for complete lead extraction because of local complications at the site of implantable devices have changed in the last 10 years. We analyze the outcome of patients who required an intervention because of a local complication between 2002 and 2010, in our Hospital. METHODS: We retrospectively studied 83 patients with a local complication that was classified according to skin integrity: 1. Integrity, and 2. Open skin. We analyzed the type of intervention: 1. Conservative approach, 2. Incomplete extraction, 3. Complete extraction. The endpoints were the needing a later intervention and a complete removal during follow up. RESULTS: The group of patients with complete system extraction showed a lower rate of re-intervention during an average follow up of 1000 days, when compared to other two groups (6.7% vs. 57.7 and 43.8%, P<.01). Incomplete extraction and conservative approach had a similar outcome, needing a complete extraction 25% and 37.5%, respectively. The skin integrity did not seem to be relevant for outcome in these two groups. An 8.4% incidence of endocarditis was observed; all of them had a previous history of incomplete extraction or conservative approach. CONCLUSIONS: Local complications treated with either a conservative approach or incomplete extraction are associated with a high rate of re-interventions, regardless of skin integrity, frequently needing final complete extraction and are associated to endocarditis.

Evolución de los pacientes con complicaciones locales en la bolsa del generador de un dispositivo implantable / Outcome of patients with local complications at the site of an implantable device

Objetivo: Las recomendaciones para la extracción completa de la bolsa de dispositivos implantables por problemas locales han cambiado. Analizamos la evolución entre 2002 y 2010 de los pacientes que requirieron una intervención por una complicación local en nuestro centro. Métodos: Ochenta y tres pacientes tuvieron un problema local de la bolsa que se clasificó según integridad de la piel: 1. Íntegra y 2. Abierta, y el tipo de intervención realizada: 1. Conservadora, 2. Extracción parcial y 3. Extracción completa. El objetivo primario fue la necesidad de reintervención posterior y la de extracción total durante el seguimiento. Resultados: El grupo de pacientes con extracción completa presentó una menor tasa de reintervención durante el seguimiento medio de 1,000 días comparado con los otros 2 grupos (6.7 vs. 57.7 y 43.8%, p < 0.01). La extracción parcial y la actitud conservadora mostraron una evolución parecida con una tasa de extracción completa final del 25% y del 37.5%. Se observó una incidencia de endocarditis del 8.4%; todos con antecedente de extracción parcial o actitud conservadora. Conclusiones: Las complicaciones de la bolsa, independientemente de la integridad de la piel, tratadas conservadoramente o con extracción parcial se asocian a alta tasa de reintervenciones, necesidad de extracción completa y evolución a endocarditis.

Objective: The recommendations for complete lead extraction because of local complications at the site of implantable devices have changed in the last 10 years. We analyze the outcome of patients who required an intervention because of a local complication between 2002 and 2010, in our Hospital. Methods: We retrospectively studied 83 patients with a local complication that was classified according to skin integrity: 1. Integrity, and 2. Open skin. We analyzed the type of intervention: 1. Conservative approach, 2. Incomplete extraction, 3. Complete extraction. The endpoints were the needing a later intervention and a complete removal during follow up. Results: The group of patients with complete system extraction showed a lower rate of reintervention during an average follow up of 1000 days, when compared to other two groups (6.7% vs. 57.7 and 43.8%, P<.01). Incomplete extraction and conservative approach had a similar outcome, needing a complete extraction 25% and 37.5%, respectively. The skin integrity did not seem to be relevant for outcome in these two groups. An 8.4% incidence of endocarditis was observed; all of them had a previous history of incomplete extraction or conservative approach. Conclusions: Local complications treated with either a conservative approach or incomplete extraction are associated with a high rate of re-interventions, regardless of skin integrity, frequently needing final complete extraction and are associated to endocarditis.

Value of early cardiovascular magnetic resonance for the prediction of adverse arrhythmic cardiac events after a first noncomplicated ST-segment-elevation myocardial infarction.

BACKGROUND: Infarct size (IS) determined by cardiac magnetic resonance (CMR) has proven an additional value, on top of left ventricular ejection fraction (LVEF), in prediction of adverse arrhythmic cardiac events (AACEs) in chronic ischemic heart disease. Its value soon after an acute ST-segment-elevation myocardial infarction remains unknown. Our aim was to determine whether early CMR can improve AACE risk prediction after acute ST-segment-elevation myocardial infarction. METHODS AND RESULTS: Patients admitted for a first noncomplicated ST-segment-elevation myocardial infarction were prospectively followed up. A total of 440 patients were included. All of them underwent CMR 1 week after admission. CMR-derived LVEF and IS (grams per meter squared) were quantified. AACEs included postdischarge sudden death, sustained ventricular tachycardia, and ventricular fibrillation either documented on ECG or recorded via an implantable cardioverter-defibrillator. Within a median follow-up of 2 years, 11 AACEs (2.5%) were detected: 5 sudden deaths (1.1%) and 6 spontaneous ventricular tachycardia/ventricular fibrillation. In the whole group, AACEs associated with more depressed LVEF (adjusted hazard ratio [95% confidence interval], 0.90 [0.83-0.97]; P<0.01) and larger IS (adjusted hazard ratio [95% confidence interval], 1.06 [1.01-1.12]; P=0.01). According to the corresponding area under the receiver operating characteristic curve, LVEF ≤36% and IS ≥23.5 g/m(2) best predicted AACEs. The vast majority of AACEs (10/11) occurred in patients with simultaneous depressed LVEF ≤36% and IS ≥23.5 g/m(2) (n=39). CONCLUSIONS: In the era of reperfusion therapies, occurrence of AACEs in patients with an in-hospital noncomplicated first ST-segment-elevation myocardial infarction is low. In this setting, assessment of an early CMR-derived IS could be useful for further optimization of AACE risk prediction.

Ablation or conservative management of electrical storm due to monomorphic ventricular tachycardia: differences in outcome.

AIMS: Electrical storm (ES) is a life-threatening condition that predicts bad prognosis. Treatment includes antiarrhythmic drugs (AAD) and catheter ablation (CA). The present study aims to retrospectively compare prognosis in terms of survival and ES recurrence in 52 consecutive patients experiencing a first ES episode. METHODS AND RESULTS: Patients were admitted from 1995 to 2011 and treated for ES by conservative therapy (pharmacological, 29 patients) or by CA (23 patients), according to the physician's preference and time of occurrence, i.e. conservative treatments were more frequently administered during the first years of the study, as catheter ablation became more frequent as the years passed by. After a median follow-up of 28 months, no differences either in survival (32% vs. 29% P = 0.8) or in ES recurrence (38% in ablated vs. 57% in non-ablated patients, P = 0.29) were observed between groups. Low left ventricle ejection fraction (LVEF) was the only variable associated with ES recurrence in ablated patients. When including patients with LVEF > 25%, ES recurrence was significantly lower in ablated patients (24 months estimated risk of ES recurrence was 21% vs. 62% in ablated and non-ablated patients, respectively); however, no benefit in survival was observed. CONCLUSION: Our data suggest that in most patients, especially those with an LVEF > 25%, catheter ablation following a first ES episode, decreases the risk of ES recurrence, without increasing survival.

Syncope and bundle branch block. Diagnostic yield of a stepped use of electrophysiology study and implantable loop recorders.

INTRODUCTION AND OBJECTIVES: The objective of this study was to determine the diagnostic yield of a stepped protocol involving an electrophysiologic study (EPS) and implantable loop recorders (ILR) in patients with syncope and bundle branch block (BBB). METHODS: Eighty-five consecutive patients referred for syncope and BBB after initial non-diagnostic assessment underwent EPS including a pharmacological challenge with procainamide. Those patients without indication for defibrillator implantation received ILRs. Follow-up continued until diagnosis or end of battery life. RESULTS: The EPS was diagnostic in 36 patients (42%). The most frequent diagnoses were paroxysmal atrioventricular block (AVB) (n=27), followed by ventricular tachycardia (VT) (n=6). All patients with VT had structural heart disease; left BBB was more prevalent in this group. Thirty-eight patients received ILRs and diagnosis was achieved in 13 (34%) of them; paroxysmal AVB (n=10) was the most frequent diagnosis. Median follow-up to diagnosis of paroxysmal AVB was 97 days (interquartile range 60-117 days). Paroxysmal AVB was more frequent in patients with right BBB and prolonged PR interval and/or axis deviation. We found no occurrence of VT or arrhythmic death during follow-up. CONCLUSIONS: The most common etiology of syncope in patients with BBB was paroxysmal AVB, followed by VT. The stepped use of EPS and ILR in negative patients enables us to safely achieve a high diagnostic yield, given that VT is usually diagnosed during EPS.

Acute and chronic pulmonary vein reconnection after atrial fibrillation ablation: a prospective characterization of anatomical sites.

BACKGROUND: Arrhythmia recurrence after atrial fibrillation (AF) ablation is often associated with pulmonary vein reconnection (PVR). We prospectively examined anatomical sites of both acute and chronic PVR. METHODS: One hundred and fifty AF patients underwent PV wide encirclement and sites where immediate electrical isolation (EI) occurred were tagged using electroanatomic mapping/CT integration (Cartomerge, Biosense Webster, Diamond Bar, CA, USA). After 30 minutes PVs were checked and acute PVR sites marked at reisolation. Chronic PVR sites were marked at the time of repeat procedures. RESULTS: On the left, immediate EI sites were predominantly on the intervenous ridge (IVR) and PV-left atrial appendage (PV-LAA) ridge. On the right they were at the roof, IVR, and floor of the PVs. Ninety-eight of one hundred and fifty patients had PVs checked after >30 minutes. Thirty-two of ninety-eight had acute PVR. This was mostly on the IVR and PV-LAA ridge on the left (88%), and on the roof and IVR on the right (78%). At repeat procedure, 38/39 patients had chronic PVR, predominantly on the IVR (61%) and PV-LAA ridge (21%) on the left, and on the roof, IVR, and floor of the right PVs (79%). There was minimal acute or chronic PVR posteriorly. Acutely PVR occurred close to the immediate EI site 60% of the time, but only 30% of the time chronically. CONCLUSION: Acute and chronic PVR sites have a preferential distribution. This may be determined by anatomical and technical factors. Knowledge of immediate EI sites may be beneficial acutely, but with chronic PVR a careful survey is required. These findings may help target ablation, improving safety and success.